Worse Unprofessional billing

the last time i wrote a review was regarding my account billing not being accurate and now the same problem has gotten worse. how can a company so big make mistakes like this you give a credit and i have just spoken to a lady for 20 minutes on the phone. where do you think i must get the airtime and money im a single mom and then i still have to worry about all this nonsense you through at me. could someone please get this sorted and i totally refuse to pay for your system error, so dont come back to with payments on side im not signing for that game.